libcamera: Drop emitter object pointer from signal arguments

Many signals used in internal and public APIs carry the emitter pointer
as a signal argument. This was done to allow slots connected to multiple
signal instances to differentiate between emitters. While starting from
a good intention of facilitating the implementation of slots, it turned
out to be a bad API design as the signal isn't meant to know what it
will be connected to, and thus shouldn't carry parameters that are
solely meant to support a use case specific to the connected slot.

These pointers turn out to be unused in all slots but one. In the only
case where it is needed, it can be obtained by wrapping the slot in a
lambda function when connecting the signal. Do so, and drop the emitter
pointer from all signals.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 9d35618d..4e1c2b7c 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -1524,7 +1524,6 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
 
 /**
  * \brief Slot to handle completed buffer events from the V4L2 video device
- * \param[in] notifier The event notifier
  *
  * When this slot is called, a Buffer has become available from the device, and
  * will be emitted through the bufferReady Signal.
@@ -1532,7 +1531,7 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
  * For Capture video devices the FrameBuffer will contain valid data.
  * For Output video devices the FrameBuffer can be considered empty.
  */
-void V4L2VideoDevice::bufferAvailable([[maybe_unused]] EventNotifier *notifier)
+void V4L2VideoDevice::bufferAvailable()
 {
 	FrameBuffer *buffer = dequeueBuffer();
 	if (!buffer)